This invention relates to cleaning, and relates more particularly but not exclusively to apparatus for the cleaning of surfaces.
There are certain articles and processes which require scrupulous cleanliness for proper functioning; for example photo-lichographic masks for semiconductor production require to be essentially free of surface particles in order that resultant integrated circuits should not be defective by reason of masking faults. While precautions can be taken to minimise surface contamination (for example, air filtration to trap airborne dust particles), it is essential or desirable to be able to clean surfaces in a manner that avoids damage to or dissolution of the surface, and is preferably easy to perform.
According to a first aspect of the present invention there is provided a surface cleaning apparatus for cleaning a first selected surface of a workpiece, the surface cleaning apparatus comprising a first pair of rotatably mounted surface-cleaning rollers, a selectively actuable workpiece urging means mounted in opposition to said first pair of rollers for selectively urging a workpiece present between said workpiece urging means and said first pair of rollers into contact with said first pair of rollers, and selectively operable roller lifting means for selectively and independently lifting either or both of said first pair of surface cleaning rollers away from said workpiece urging means and out of contact with a workpiece therebetween.
According to a second aspect of the present invention there is provided a surface cleaning apparatus for cleaning a first selected surface of a workpiece, the surface cleaning apparatus comprising a first pair of romatably mounted surface-cleaning rollers, a workpiece urging means mounted in opposition to said first pair of rollers to urge a workpiece present between said workpiece urging means and said first pair of rollers into contact with said first pair of rollers, and a workpiece path-defining means defining the path of a workpiece through said surface cleaning apparatus between said first pair of surface-cleaning rollers and said workpiece urging means with said first selected surface rending to be in contact with said first pair of surface-cleaning rollers.
Preferably, said workpiece path-defining means defines a workpiece path which is substantially vertical.
In said first and second aspects of the present invention, said workpiece urging means may comprise a second pair of rotatably mounted surface-cleaning rollers, the rollers of said first and second pairs being individually mutually opposed to form respective roller bights. In the second aspect of the invention, the roller lifting means preferably operates simultaneously and conjointly to lift both rollers of a bight to open the bight for the passage of the leading end of a workpiece between respective pairs of mutually separated rollers on either side of the moving workpiece.
These preferred forms of the invention enable the simultaneous surface cleaning of selected first and second surfaces of a workpiece, which surfaces are mutually opposed and may be opposite major faces of a laminar workpiece.
Each said surface-cleaning roller in either aspect of the invention is preferably provided with a respective adherent peripheral surface of a first degree of adhesive tackiness. Each said surface-cleaning roller or each said pair of surface-cleaning rollers is preferably provided with a respective backup adhesive roller in rolling contact therewith, each said backup adhesive roller being provided with a respective adherent peripheral surface of a second degree of adhesive tackiness greater than said first degree of adhesive tackiness.
One or both surface-cleaning rollers in each roller bight is preferably provided with roller driving means for driving a workpiece through the bight when the bight is closed. The roller driving means is preferably reversible for bi-directionally driving the workpiece through the surface cleaning apparatus.
Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawing which is a schematic diagram of a preferred embodiment.